Speaking to Sky Sports, Van Dijk said: "I think it was quite obvious that it was going to be a second yellow.
"Obviously I think it was pretty clear [from what I said to the referee]. It was no coincidence that a minute later he scores the winner.
"He [Attwell] made a mistake in my opinion and I told him that. It was quite obvious I think and everyone on the sidelines knew it was supposed to be a yellow.
"There is a linesman there, a fourth official. There is VAR there and a referee, and he doesn't get a second yellow. I'm not saying this is the reason we lost today, but it was a big moment in the game."